Matter

Dielectric Duke

This Duke “D” is being lit by electromagnetic waves that are normally invisible to the human eye. But they can be seen here thanks to a dielectric metamaterial filter created by Willie Padilla. Metamaterials are synthetic materials composed of individual, engineered cells that together produce properties not found in nature. In this case, that’s the ability to absorb energy in any specific range across the electromagnetic spectrum and convert it into heat.

Shooting Nanowires

The “shooting star” patterns in this Mahato Contest Runner-Up aren’t just dazzling to look at – they may also be useful electronics. Graduate students Kristen Collar and Jincheng Li first found these patterns while growing thin films of the semiconductor gallium arsenide. The “stars” start as droplets of liquid gallium on the film surface; as the film grows, they slowly move across the surface, leaving small solid trails -- nanowires -- in their wake.

Magnetic Webs

Sand, snow and other granular materials have a split personality; they can flow through your fingers like a liquid, but if you squeeze them too hard, they “jam,” becoming firm like a solid. Engineers would like to harness this dual nature to create flexible scaffolds for soft robotics or buildings – but first, they must learn to control their behavior. Using transparent beads, researchers in Robert Behringer’s lab investigated how jamming changes when some particles in a material are magnetized.

Genetic Code to Computer Code

Tiny spirals of DNA can encode more than just the color of your eyes or the shape of your nose. Using self-assembling DNA wires, Duke engineer Chris Dwyer is building optical computing chips so compact that you could cram 5,000 movies on a single CD-sized disc. The chromophores (red dots) absorb light and transform it into packets of energy called excitons. Then these excitons leap from chromophore to chromophore in a specific pattern.

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